Functional Ability,Neighborhood Resources and Housing Satisfaction among Older Adults in the U.S.

The purpose of this study was to explore neighborhood resources that influence the housing satisfaction of older adults. The study included 10,146 participants from the 2009 panel of the American Housing Survey who were 65 years and older. Hierarchical regression modeling was performed to examine older adults’ perceptions of neighborhood resources and consequently the role these resources play in predicting housing satisfaction among community dwelling and residents of assisted living, controlling for age, sex, ethnicity, education, and housing maintenance. In addition, three levels of physical functioning among residents of assisted living were examined. Results showed that there were differences in housing satisfaction by residences and levels of physical functioning. Subjective evaluations of neighborhoods and the near surrounds were significant predictors of housing satisfaction. Results of the study suggest that policy makers and housing professionals need to continue to consider the role of supportive neighborhoods and social environments in promoting successful aging particularly for frail older adults.     

Variable selection and prediction in biased samples with censored outcomes

With the increasing availability of large prospective disease registries, scientists studying the course of chronic conditions often have access to multiple data sources, with each source generated based on its own entry conditions. The different entry conditions of the various registries may be explicitly based on the response process of interest, in which case the statistical analysis must recognize the unique truncation schemes. Moreover, intermittent assessment of individuals in the registries can lead to interval-censored times of interest. We consider the problem of selecting important prognostic biomarkers from a large set of candidates when the event times of interest are truncated and right- or interval-censored. Methods for penalized regression are adapted to handle truncation via a Turnbull-type complete data likelihood. An expectation–maximization algorithm is described which is empirically shown to perform well. Inverse probability weights are used to adjust for the selection bias when assessing predictive accuracy based on individuals whose event status is known at a time of interest. Application to the motivating study of the development of psoriatic arthritis in patients with psoriasis in both the psoriasis cohort and the psoriatic arthritis cohort illustrates the procedure.     

A bayesian analysis of the mixed linear model

The mixed model is defined. The exact posterior distribution for the fixed effect vector is obtained. The exact posterior distribution for the error variance is obtained. The exact posterior mean and variance of a Bayesian estimator for the variances of random effects is also derived. All computations are non-iterative and avoid numerical integrations.     

Bayesian autoregressive filter and squared gain estimation

This article describes a Bayesian small sample approach to making inferences for the operator (or filter) and squared gain of a p — th order Gaussian univariate autoregressive process. Simultaneous pos¬terior probability bands are developed for the real and the imaginary parts of the frequency-response function of an autoregressive operator as well as for the squared gain of an autoregressive process.     

A projection pursuit index for large <Emphasis Type=Italic>p</Emphasis> small <Emphasis Type=Italic>n</Emphasis> data

In high-dimensional data, one often seeks a few interesting low-dimensional projections which reveal important aspects of the data. Projection pursuit for classification finds projections that reveal differences between classes. Even though projection pursuit is used to bypass the curse of dimensionality, most indexes will not work well when there are a small number of observations relative to the number of variables, known as a large p (dimension) small n (sample size) problem. This paper discusses the relationship between the sample size and dimensionality on classification and proposes a new projection pursuit index that overcomes the problem of small sample size for exploratory classification.     

The Impact of Organizational Form on Gendered Labour Markets in Engineering and Law

It is well known that occupations are differentially gendered and explanations for such gendering usually focus on structure and process in the labour market. However little is known of the fine detail of the way in which labour markets perform for particular occupations in particular local contexts. This article is based on micro-sociological research on the professional labour markets for law and engineering professionals in the city of Hobart, Australia. It addresses a discrepancy in women's participation and promotion rates in each of these professions: the proportion of women in high positions in engineering matches their educational qualification rates while that in law is considerably lower than educational qualification rates would suggest. The paper proposes that the explanation can be found in the respective organizational patterns of the two professions. Engineering is practised in large-scale bureaucratic organizations where formal rules govern recruitment and promotion, where equal opportunities legislation literally applies, and where a strict separation is maintained between public and domestic spheres. By contrast, law is practised in collegial partnerships where informal judgements govern recruitment and promotion, where the letter of equal opportunities legislation need not be applied, and where advancement depends on the subordination of the domestic to the public sphere.     

Callosal inhibition: the key to the brain code

A mechanism for interhemispheric communication is proposed based upon the assumption of homotopic callosal inhibition. The implied pattern of cortical activity in each cerebral hemisphere is shown to be the mirror-image and "photographic negative" of the contralateral pattern. Mirror-imagery is a direct consequence of (1) approximate cerebral hemispheric bilateral symmetry and (2) homotopic callosal connections. The photographic negative relationship is a direct consequence of (1) bilaterally symmetrical activation of the cortex via subcortical "attentional" mechanisms and (2) inhibition by a unilaterally established engram of an identical cortical pattern contralaterally. In language generation and understanding, excitation predominantly in the left hemisphere produces on the right inhibition of language-related neurons as well as excitation of all surrounding "contextual" neurons. The suggested dichotomy of verbal and contextual functions of the cerebral hemispheres is shown to be supported by previous findings concerned with cognition in brain-damaged patients. Unlike earlier suggestions of linguistic and paralinguistic specializations in the left and right, the mirror-image negative hypothesis is based upon an explicit physiological process rather than unspecified differences in "information processing."     

Progressive multi-state models for informatively incomplete longitudinal data

Progressive multi-state models provide a convenient framework for characterizing chronic disease processes where the states represent the degree of damage resulting from the disease. Incomplete data often arise in studies of such processes, and standard methods of analysis can lead to biased parameter estimates when observation of data is response-dependent. This paper describes a joint analysis useful for fitting progressive multi-state models to data arising in longitudinal studies in such settings. Likelihood based methods are described and parameters are shown to be identifiable. An EM algorithm is described for parameter estimation, and variance estimation is carried out using the Louis’ method. Simulation studies demonstrate that the proposed method works well in practice under a variety of settings. An application to data from a smoking prevention study illustrates the utility of the method.